Rail bond for electric railways and method for producing the same



March 16 9 1922 5: 1,576,590

-' R. FORTEP; ET AL RAIL BOND FOR ELECTRIC RAILWAYS AND METHOD FORPRODUCING THE SAME Filed Jun 10, 1924 2 Sheets-Sheet 1 dnwmv dMeiuQ LMarch 16., 1925-.

R. FORTER ET AL RAIL BOND FOR ELECTRIC RAILWAYS AND METHOD FOR PRODUCINGTHE SAME z Sheets-Sheet 2 Filed June 10, 1924 3g AMM WK Patented Mar.16, 1926.

a UNITED" STATES PATENT OFFICE.

ROBERT FORTER, OF ZURICH, AND HULDREICH ALTORFER, 0F R'UTI, SWITZERLAND,ASSIGNORS TO EMBRU-WERKE A.-G., OF RUTI, SWITZERLAND.

RAIL BOND FOR ELECTRIC RAILWAYS AND METHOD FOR I RODUClIR'Ci THE SAME.

Application filed June 10, 1924. Serial No. 719,062;

To all whom it may concern:

Be it known that we, ROBERT FORTER, a citizen of the Republic ofSwitzerland, residing at Zurich, Republic of Switzerland, and HULDREICHAL'roRFnR,-a citizen of the Republic of Switzerland, residing at Ruti,Republic of Switzerland, have invented certain new and usefulImprovements in Rail Bonds for Electric Railways and Methods forProducing the Same, of which the fol-.

lowing is a specification.

This invention relates to an improved rail bond for electri-c'railwaysand to a method for the production of the same.

For electrical connection of rail ends in electrically operated railwaysit is necessary to employ means which ensure dependable and lastingelectrical contact besides being of suflicient mechanical strength andsolidity. The rail bonds heretofore used sufier from the drawback thatthey fail to answer fully one or other of these conditions or else theyare too expensive to manufacture.

The rail bond subject of this invention fully answers the aforesaidrequirements.

According to the invention each end of an electrical conductor ispressed into a socket (or orifice) having a wide portion at the entranceend and formed in a weldable block consisting of a seamless piece ofmetal of suitable profile, the full crosssection of the conductorentering the wide portion of the socket and the residual part of theconductor within the block being pressed flatwise and compacted withoutbeing materially broadened whereby to effect a mechanically andelectrically durable connection which excludes the formation ofelectrically insulating separation (oxidation) surfaces between theconductor and the blocks.

In the production of the described rail bond, for the purpose ofobtaining the mechanically and electrically durable connection betweenthe electrical conductor and the block, this block is formed of atubular member having two opposed broad longitudinal ribs. This memberis positioned on the conductor and then the central portion only of thetubular member is compressed until it is substantially flush with theplane of the ribs. This forces the material of the block into intimatecontact with the conductor and somewhat flattens the I conductor at theplace where the pressure is applied. The original cross-sectional shapeof the conductor, at the point where it enters the tubular member,remains unaltered because the tubular member itself at this point is notcompressed nor altered in its shape. While the conductor is flattenedwhere the pressure is applied there is.

-no material widening of the conductor in a direction at'right angles tothe direction of pressure.

In a preferred form of the conductor the conductor is bent in such amanner that the axes of the parts entering the contact pieces areparallel to one another and also to the direction of the rails so thatthe parts entering the contact pieces are practically subjected only totension or pressure but not to shear or bending effort.

A preferred method of producing rail bonds for electric railwayscomprising a conductor and contact pieces on the ends thereof consistsin lacing on a conductor tubular members each serving for the formationof two contact pieces spacing said members apart a distancecorresponding to the length of the rail bonds, subjecting the centralpart of each member to pressure, and finally halving each membertransversely of the direction of the conductor.

By the particular shape of the contact piece the further advantage isobtained, that the wall-thicknessof the contact piece, especially in thedirection of the width, may be kept very large and thus relatively largedimensions may be given to the contact piece without necessitating a toostrong pressure for producing the connection. The con-. tact piece maybe welded directly. to the rail and a solid connection thereby madebetween the contact piece and the rail.

The invention is illustrated by way of examples iii the accompanying.rawlngs, in

which Fig. 1 is an elevation of the first exp e- Fig. 2 is a plan andFig. 3 is a section on the line :v'm of Fig. 1. t

Fig. 4 shows a contact block before it is submitted to pressure.

' bond.

Figs. 9 and 10 represent the two stages of the method for manufacturingthe rail bond.

In the drawings 1 denotes the electric conductor which may be formed,for example, of a rope of copper wire; 2 denotes the contact pieces ofwhich one is connected with each end of the conductor. Each contactpiece consists preferably of wrought iron so that it may be welded inmanner known per se to the head of the rail at each side of the joint byan autogenous or electric welding process. The contact pieces eachconsist initially, as shown in Fig. 4:, of a seamless tubular memberwhich is provided with two opposed broad longitudinal ribs and is inconsequence of substantially prismatic form (see Figs. 1, 2 and 4). Toconnect the conductor and the contact pieces the tubular member of whichFig. 4 shows its form before treatment) is laced over the end of thewire rope; the tubular member is then subjected to pressure directedtransversely of the plane of the ribs over the greater part of itslength whereby the convexed or arched portions of the wall of thetubular member are pressed into the plane of the ribs and the end of therope is pressed flat and compacted, while at the same time the stronglongitudinal ribs in the contact piece ensure against yieldinglaterally, that is prevent the end of the rope from being broadened.

In this way there is effected a substantial compacting of the materialwhich effects a good conducting and durable connection that is alsocapable of resistingmechanical stresses between the rope and the contactpiece.

Near the point where the rope enters the contact piece the latter is notcompressed so that at this point, as shown in Figs. 1 to 3, the convexedportions of the walls remain as indicatedat 3 and there is no alterationof the cross sectional form of the rope where it has to carry the entirecurrent.

To prevent any lateral yielding of the material when the contact pieceis pressed, it may be laid into a socket during the pressing period;however this is not absolutely necessary especially if a sufiicientlystrong contact .piece is used. The pressure being chiefly exerted uponthe weaker arched wall portions of the contact piece and upon the end ofthe conductor, a relatively thick iron block may be applied as contactpiece, which iron block immediately can be pressed upon the conductor,without necessitating an excessively high pressure. On the other handitis possible, to imediately weld the thick contact piece of ironpressed upon the conductor to the rail. The improved rail bond istherefore of the highest simplicity and efficacy.

In the preferred form, shown by Figs. 5, 6 and 7, the rope of copper 1serving as a conductor is bent into the form of a loop,

the axes of the tangential ends pressed into the weldable blocks 2 beingparallel to the direction of the rails. It will be evident that withsuch a formation of the conductor, the straight parts will be subjectedpractically only to tension or pressure on expansion and contraction ofthe rails but will not ,rection of the rails.

In ,the production of the rail bonds described in order to form andsecure simultaneously two blocks, profiled tubular members each doublethe length of a block are strung on the rope at given distances apart,the central portions of such members are then subjected to pressure andfinally said members are halved transversely of the direction of therope. In this way there is effected more rapid and more economicalproduction. The method has also the further advantage that theconnection between the rope and the blocks is more intimate because onthe one hand lateral yield of the material of the blocks is opposed bythe solid material at both ends of the tubular member, and also there isno untwisting of the rope such as has been experienced heretofore.

Referring to Figs. 9 and 10, the tubular member serving for theformation of two blocks has two opposed longitudinal ribs 2. For theproduction of rail bonds several such tubular members are strung on therope 1 at distances apart corresponding to the length of the bonds, andare thereafter compressed, as shown in Fig. 10, so that the convexedportions are brought into the plane of the ribs as shown in Fig. 10,with corresponding compacting and flattening of the wire rope. Thecompressed member and the rope embraced thereby is then cut throughalong the dotted line shown in Fig. 10 so that each such member formstwo blocks.

Instead of a rope of copper wire, a solid conductor may be used.

. In order to present an even bearing surface, the part of the tubularmember on one side of each contact piece which is not pressed inwardlymay be machined.

What we claim is 1 1. A rail bond comprising an electric conductor, anirqn terminal block secured to each end of the conductor, each blockcomprising a tubular portion having a central opening in which oneend ofthe conductor is inserted and having diametrically opposite broadlongitudinal ribs, the cylindrical walls of said tubular portion beingpressed inwardly toward the conductor throughout a portion of theirlength to flatten a portion of the conductor and the central opening,said longitudinal ribs serving to prevent spreading of the conductor andthe central opening in a lateral direction so that the cross-sectionalarea and also the periphery of the conductor and the opening are reducedwhereby the pressed-in material of said tubular walls compacts theconductor and fills all interstices.

2. A method of producing rail bonds for electric railways comprising aconductor and contact pieces pressed on the ends thereof, consisting inlacing on a conductor tubular members each serving for the formation oftwo contact pieces, spacing said members apart a distance correspondingto the length of the rail bonds, subjecting the central part of eachmember to pressure, and finally halving each member transversely of thedirection of the conductor.

3. A method of producing rail bonds for electric railways comprising aconductor and contact pieces pressed on the ends thereof, consisting inlacing on a conductor tubular members of iron each serving for theformation of two contact pieces, spacing said members apart a distancecorresponding to the length of the rail bonds, subjecting the centralpart of each member to pressure, halving each member transversely of thedirection of the conductor and finally machining the part of the tubularmember on one side of each contact piece which is not pressed inwardlyin order to present an even bearing surface.

In testimony whereof we have aflixed our signatures,

ROBERT FORTER. HULDREICH ALTORFER.

